Curt netto



(No Model.)

0. NETTO. PROCESS OF MAKING-SODIUM QR POTASSIUM. No. 460,985. Patented Oct. 13, 1891.

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UNITED STATES PATENT OFFICE.

oun'r NETTO, on DRESDEN, SAXONY, GERMANY.

PROCESS OF MAKING SODIUM OR POTASSIUM.

SPECIFICATION forming part of Letters Patent No. 460,985,'dated October 13, 1891.

Application filed February 14,1888. Serial No. 263,949. (No specimens.) Patented in England October 26, 1887, No. 14,602; in Germany November 5, 1887, No, 45,105 in France December 1, 1887, No. 187.349 5 in BelgiumDcoember 1, 1887, No. 79,759,

and in Austria-Hungary August 16, 1889, No. 7,693 and No. 40,262.

To all whom it may concern.-

Be it known that I, CURT NETTO, engineer, a subject of the King of Saxony, residing at Dresden, Saxony, German Empire, have invented certain new and useful Improvements in the Manufacture of Sodiuum or Potassium and in Apparatus Therefor, (for which I have obtained the following patents: in Austria- Ilungary, No. 7,693 and No. 40,262, dated August 16, 1889; in England, No. 14,602, dated October 26, 1887; in Germany, No. 45,105, dated November 5, 1887; in Belgium, No. 70,759, datedDecember 1,1887, andin France, No. 187,89, dated December 1, 1887;) and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, and to letters of reference marked thereon, which form a part of this specification.

The present invention has relation to a continuous process for the manufacture of alkali metals, as potassium, sodium, &c., and the production at the same time of alkaline carbonates from the hydroxides of the respective metals by reduction with reducing-agents, like coal or other carboniferous materials.

For the manufacture of sodium (sodium will be chosen here as an example) by the reduction of caustic soda by means of coal the result of the reduction when complete finds its expression in the following equation: NaHO+C:Na+I-I+OO. Now in the manufacture of the sodium from caustic soda it will be observed that at the beginning the separation of the sodium metal is effected at a comparatively low temperature; but that very soon, in order to maintain the separation, the employment of higher temperature becomes necessary, much to the detriment of the vessels employed in the reduction and greatlyin increase of the consumption of fuel. The course of this process shows, therefore, two different phases. In the first, wherein the reduction is eifected at a comparatively low temperature, about red heat, the formation of carbonate of soda, metallic sodium, carbonic oxide, and hydrogen can be expressed by the equation: 4:(NaHO)+2O:Na OO 2Na+1H+CO. This first phase being completed, the remaining carbon will not have to act upon the carbonate of soda formed in the first phase. This requires a considerably higher temperature than is necessary for the first phase. The second phase, comprising the process of reduction of the carbonate of soda formed in the first phase, may find its expression in the following equation: Na OO +2C: Na-I3CO. This indicates that the temperature necessary for the reduction must be more and more elevated, accordingly as the formation of carbonate of soda increases. This inconvenience occurs also in the known process which consists in throwing the canstic alkali to be reduced upon the previouslyheated coal. At first the reduction proceeds at a comparatively low temperature; but subsequently the temperature must be raised more and more until finally an interruption of the process becomes necessary in order to allow the molten mass or the scoria to be scraped or removed from the reducing-vessel. It is even necessary sometimes to provide a new reducing-vessel, as the one in use can be quickly destroyed by the molten mass and the higher temperature required after the formation of carbonate of soda.

It is the object of the present invention to obviate the inconvenience above stated, and such invention contemplates the manufacture of the alkali metals in the first phase of the process of reduction in order to have to deal with comparatively low temperatures.

In conformity with the above-mentioned observations and considerations the alkaline carbonate first formed by the reduction of caustic alkali by means of carboniferous materials will naturally mix with the caustic. alkali, so that the temperature required for the reduction necessarily becomes higher and higher. To avoid this the process forming the object of the present invention is so carried into effect that, in the first place, the mixture of the alkaline carbonate formed during the first part of the process with the caustic alkali is to a great extent avoided, and, in the second place, the carbonate produced in the first stage of the process is led away during the process of reduction continuously, or

from time to time, as maybe necessary, while ent known process, therefore, by the regular discharge of the formed carbonate and by the continual charge of the sufficiently-heated reducing material and of the caustic alkali mass to be reduced, so that the reducing action will take effect only upon the caustic alkali, and that the temperature of the reduction consequently need be only a low one.

An apparatus represented as an example on the accompanying sheet of drawings is appropriate to be employed for the working of the present process, where the caustic soda in the caustic soda, the outlet-pipe of which is provided with a regulating-faucet b.

cis the chargin -funnel for the molten caustic soda, which leads through the lid 6, the latter being provided with a charge-hole I for the coal into the retort f, made of proper material'. e., cast-steel, wrought or cast ironand wherein the reduction should take place under the influence of the coal g. The tappipe h, arranged near the bottom of the retort, is properly provided with a valve 2'. In an opening at the upper part of the retort a receiver 70, somewhat narrow, is properly arranged for condensation of the sodium. Under the outlet of this condenser is placed a reservoir Z. jacket on of clay. The gases used for heating are led through the flue w and opening 0 into flue 'n, where'they circulate around the retort. Then the gases pass through the openingp, flues r and q into the heating-space s, where they heat the vat a, and now they can be led off through opening 25 into the chimney. The charging-funnel 0 can be provided with a conical valve u. Below the tappipe 72. is placed a receiving-vessel y for the molten mass of soda formed during the reduction.

By means of such apparatus the present process is executed in the following manner: The retort is heated to about cherry-red, then it is charged by either taking off the lid e or through the charge-hole I with as much coal, preferably charcoal, as will fill about onethird of its capacity. WVhen the coal is glowing, (a few minutes are sufficient for the pur- The retort f iscovered with'a' pose,) the molten caustic soda is allowed to run from the vat a through the funnel 0 upon the glowing coal. The flow can be regulated by the faucet 1). Immediately the sodium flame becomes visible at 7c, and after a very short time the sodium flows oif'from it into the oil-reservoir Z. In the beginning it is necessary to close the valve '5 in order to keep off the atmospheric air; but in a short time, about half an hour, enough liquid mass, the greater of which is carbonate of soda, will have gathered at the bottom of the retort, so as to form at h a hydraulic closure, and 'now the valve 2' can be opened,-whereupon any excess of molten mass can freely flow off through the tap-pipe h. When after some hours the stock of coal in the retort is nearly exhausted, the flow of caustic soda is cut off by closing the faucet b, and after waiting some minutes,

until the sodium flameat is has nearlydisap-v peared, fresh coal is charged in through I, whereupon the operation recommences after having closed the opening I, which can be done, for instance, by simply placing upon it an iron cylindrical plug. It is obvious that the introduction of coal may be effected in any wayi. e., as in charging gas-generators in order to completely avoid opening the retort for charging'coal. It is not necessary to fasten the lid e by screws or wedges. It is sufficient to simply lay it in place. Any other carboniferous material may just as well be employed for the decomposition; but charcoal offers a special advantage on account of its containinga low degree of silicic acid and a comparatively high degree of alkali in its ashes. On account of the absence of silicic acid stubborness of theliquid mass is avoided, and by reason of the comparatively high degree of alkali in its contents the losses of alkali become comparatively small, notwithstanding the unavoidable sodium flame. The mass can be separated from particles of coal contained in it by lixiviation and the solution can be worked to carbonate of soda or regenerated into'caustic soda.

The process can be executed also in an apparatus Where the heating of the retort is not effected from the outside (when similar to the process of manufacturing water-gas an intermittent periodical working is adopted) by alternately causing the coal contained in the apparatus to glow under access of air or other gases and introducing the soda, then again leading air or burning gases into the apparatus to heat the coal, then again bringin g in soda, &c. For this purpose the apparatus represented by Fig. 2 is appropriate. The large vertical cylinder f, made of boiler-sheets and matted in with brick-work, is provided on its head-plate with a number of reservoirs K, Wherefrom the condensed alkali metal can flow into the oil-reservoir Z. It is further provided with an opening I, which can be closed by a lid e, to throwin the coal and with a chargingfunnel c for the molten soda. To the conical bottom of the cylinder is attached a tap-pipe h, having a means to close it, by which the formed products can flow into a receptacle placed below, which is best provided with wheels, while near the bottom tuyeres 1; are arranged, through which air or burning gases may be introduced for the purpose of heating the coal. The upper head-plate may also be provided with asiphon-pipe r. The funnelpipe of the charging-funnel c is best provided with a perforated curved or conical divider to divide the molten mass of soda. The apparatus is filled with glowing charcoal, and then air, or a mixture of air and. inflammable gas, is blown in till the necessary temperature is obtained. Then the flow of gases is cut oif and the caustic soda is admitted as long as any sodium separates in the apparatus, whereupon the gases in it are drawn off, and then the necessary temperature is re-established by the introduction of air or burning gases. If it be desired to accelerate the process in this apparatus by heating from outside, the brickwork surrounding the cylinder can be provided with fire or gas flues. The inner heat can be produced either by introducing air to the glowing coal, thus producing combustion, or by introducing inflammable or burning gases or mixtures of gases. coal is consumed, fresh coal is filled in, which can be effected by simply throwing it in, orin any other wayt'. e., in a manner similar to that employed in charging gas-generators.

In this process thus illustrated by different examples it is of course not necessary to introduce the soda in liquid state, though it seems to be most convenient and advantageous. It can as wellin special cases be introduced in solid blocks. Moreover, instead of pure caustic soda impure sorts may be employedi. a, what is known as bottoms.

The advantages obtained by my presentprocess are in short the following:

First. The process is carried on, as explained above, at an equal comparativelylow tem perature-i. 6., cherry-red heat. The retorts, therefore, are not attacked, and hence wear a long time, so that even cast-iron can be employed as the material in building them.

Second. As the retorts remain in the kiln and are not withdrawn, as in the case with the crucibles in other processes, the dimensions of the same can be considerable and they can be covered with preserving-coating of clay.

Third. By the employment of vertical retortsthe disadvantages of horizontal retorts consisting in a slight sagging of the same, whereby the preserving clay coat falls off, are avoided.

Fourth, As the lid of the horizontal retorts has to be screwed on, and as the highly-heated gases formed in the retort cannot escape after the openings leading to the condensers 7c are obstructed, the danger of explosion becomes im minent and explosions have in fact occurred As soon as the on account of the lively development of hydrogen in the beginning. This danger of explosion is completely avoided in the present process, as the quantity of the soda introduced can at all times be regulated by the position of the faucet 71 or completely shut off. Moreover should the pressure in the retort by any reason-say, by negligence-become too high, the iron plug d at I operates like a safetyvalve, and will belifted by the excess of power, so that the gases can freely escape.

Fifth. The present process is very simple and convenient compared to the other known processes, wherein it is very disagreeable, even dangerous, to handle an obstructed receiver when luted by the heat, for even when removed burning sodium vapors under pressure rush upon the workman, andif he should not succeed in removing the obstruction in a few minutes, nothing can be done except abandon the retort and quench the fires. Again, this disagreeable evacuation of the retorts and the charging of the same, the fixing of the lids on the hot retorts during the operation are not necessary with the present process, wherein by a simple closing off of the faucet in the alkali supply-pipe the action ceases by itself after one or two minutes.

The process constituting my invention admits of the use of less valuable products containing sodat'. a, the bottoms-the use of which has heretofore been economically impracticable, as the charge had to be held concentrated as much as possible.

Seventh. The present process admits of a continuous operation with all its advantages, consisting in easy work, sparing of the retorts and the coatings, avoiding the cooling off, with the bad influence produced upon the neighboring retorts in the kiln while charging or discharging one retort, sparing of the kiln, economizing fuel, &c.

Having described my invention, what I claim is The process forthe production of potassium or sodium from their hydroxides in a continuous operation, which consists in bringing the caustic alkali into contact with the reducing carboniferous matter at such a low temperature that only the caustic alkali is reduced to a metallic state, while the alkali carbonate simultaneously formed remains undecomposed and is withdrawn out of the reach of the reducing carboniferous matter without interruption of the reducing process or the 'admission of air to the reducing-vessel, the

caustic alkali being charged continuously into the reducing vessel or retort during the reducing operation, substantially as described. In testimony whereof I affinmy signature in presence of two witnesses.

OURT NET 0.

Witnesses:

HERMANN KUHFUS, FRITZ MOELLENHOFF. 

